OpenAI is fast losing ground to rival Google in the chatbot race, according to new data from SimilarWeb, with the stalwart ChatGPT bot feeling the squeeze since the much-hailed release of the Gemini 3 models.

Releasing its first Global AI Tracker of 2026, the intelligence platform found that Google’s Gemini has recently eeked past the 20% share benchmark, a staggering rise from barely above 5% only a year ago.

At the same time, ChatGPT has seen its market share fall from around 87% twelve months ago to just over 64% at the beginning of 2026, a marked counter‑trend to Gemini’s success, but perhaps unsurprising given that 95% of ChatGPT users still rely on Google search.

Since its launch late last year, Google’s latest genAI offering has seen explosive growth, with the Gemini app now seeing more than 650 million users per month, up from 450 million last summer. 

That still puts Google’s bot well behind ChatGPT, however, which counts monthly active users of around 810 million, claiming 50% of downloads on mobile devices to become the fastest app to reach 1 billion global downloads last year, according to Sensor Tower data.

But OpenAI’s momentum has slowed, with monthly active users only growing by 6% in the second half of last year, with SimilarWeb’s stats perhaps showing that once loyal GPT-ites are curious about what Google’s AIs have to offer.

Gemini is near the sole beneficiary of this huge shift, according to the data. For example, SimilarWeb found that Anthropic’s Claude, widely considered one of ChatGPT’s main rivals, has experienced next to no growth in its market share over the last twelve months, rising from 1.5% to 2%.

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The same story holds for the likes of Grok, going from 2.1% six months ago to 3.4% today, and Perplexity, which saw some fluctuation in its market share over the year before settling at 2%, a scant 0.1% rise from its position twelve months back.

Unfortunately for Microsoft, it also looks to be losing the genAI race for the moment, with Copilot’s market share holding steady at between 1.1% and 1.5% over the year, and the consumer-facing Copilot AI attracting only tens of millions of users, amounting to essentially flat-line growth.    

“The centre of gravity in digital discovery is shifting,” said Or Offer, Co-Founder & CEO of Similarweb.

“AI isn’t replacing search, it’s expanding the discovery ecosystem. Brands that understand and optimise their visibility in these moments will define the next decade of digital competition.”